Structure of Mobile GIS

7.1 Structure of Mobile GIS

  Among the different mobile GIS architectures, the ‘Stand Alone Client’ GIS architectures is the simplest one, in a way that it can be used even in offline i.e. without internet connection (Mobaraki et al., 2006). By using this architecture, mobile GIS software and the customized application reside entirely on a mobile device. However, due to limited storage space in mobile devices, large geo-data or complicated GIS analyses are very hard to perform independently in a smartphone or tablet. On the other hand, in ‘Client Server’ architecture, the geo-data is placed to a separate server or computer and served to the client (mobile device such as smartphone or tablet) by GIS server software through a wireless network. Nevertheless, continuous connection is required between the server and client to perform the activities which reduce the flexibility, as if the connection fails, the mobile GIS will no longer work. Whereas, in the ‘Distributed Client Server’ architecture, apart from storing all geo-data at a server some part of the data is placed into client devices. Therefore, the mobile GIS is useable even if it is not connected with server. Later, the data is synchronised when it is connected to the server. In this case, the client devices store geospatial data in a geo-data cache located in a temporary GIS storage space or a flash memory card which is also used in offline mode (without connected with central server). The customized datasets are downloaded and synchronized from the server when it is connected. Additionally, the collected spatial data is also stored in the server, therefore, this functionally is advantageous the exchange and sharing of spatial data between stakeholders from different jurisdictional levels. The connectivity of GIS architecture of this approach is shown in Figure 7.1.

  Figure 7.1: Illustrations of the architecture of mobile GIS (ESRI, n.d.)

  Alternatively, Web-GIS application is another option to make the application services available to others within and outside from the application hosting organization. The system in this case consists of at least a server and a client, where the server is a GIS server and the client is a web browser by using desktop application or mobile application. The main advantage is that it does not matter how far apart the server and client might be from each other. In addition, considering the costing of individual GIS software as well as a using the Web-GIS by a large number of users simultaneously it is cost effective (Ananda et al., 2016)(Ananda et al., 2016)(Ananda et al., 2016). Besides, because of the simple design of Web-GIS, general public users who are not experts in GIS, can easily use this application. However, smooth internet access is always required to connect the server for using the application. Nowadays, Hybrid apps which are built on

  a combination of native (stand-alone client) and web app technologies are quite promising. Instead of targeting a mobile browser, hybrid applications target a Web View hosted inside a native container. This enables them to do things like access hardware capabilities of the mobile device. Hence, Hybrid Web-GIS apps with cache feature facilities would be the better option to develop an app of proposed decision tree for multi-hazards susceptibility assessment as because it would also be workable even in offline situation (i.e. without internet).